Grid computing services, utility-based data centers, and other types of resource-on-demand systems are becomingly increasingly popular as a means for efficiently and cost-effectively taking advantage of computer resources to meet the computing demands of users. In certain situations, many resource-on-demand systems may be available for running a workload of a user. However, only some of those systems may actually have the capacity to run the workload. Currently, there may be no automated process for determining which resource-on-demand system has the capacity to accept and run a new workload.